testRunner.py clone fields on db copy

what seems to be some recent changes to pyDAL are causing our method for
copying fields to fail since we are trying to assign a field to a new
table while it is already assigned to it's parent. Cloning the field
allows us to have a new field assigned to the new table.
2 jobs for feature-s/server_unit_tests in 28 seconds (queued for 1 second)
Status Job ID Name Coverage
  Test Tools
passed #71762
test_tools

00:00:05

 
  Test Unit
passed #71763
web
test_server_unit

00:00:23